In image forming apparatuses such as printers, copiers and facsimile machines, the process unit is generally adapted to be removably mounted in the apparatus body for the purpose of replacing a consumable article. To manage use conditions of individual units for ensuring proper replacement of consumable articles, such apparatuses include one which is arranged to permit a user to perform a unit mounting/dismounting operation only when the apparatus is in a state to be able to confirm the mounting/dismounting of the unit. For instance, an image forming apparatus set forth in Patent Document 1 is arranged to permit the dismounting of a developing unit when a development rotary adapted to be removably mounted with the developing unit is rotatably positioned at a predetermined dismounting position, and is also arranged to inhibit the dismounting of the developing unit when the development rotary is positioned otherwise. Since the apparatus positions the development rotary under control of a controller, the apparatus is able to confirm the unit mounting/dismounting operation performed by the user.
On the other hand, the image forming apparatus of this type is required to consume less power in a state where an image forming operation is not performed or to reduce a so-called standby power requirement. To achieve this object, an apparatus has been proposed which is adapted to deactivate a power supply circuit for supplying electric power to a high power load such as a motor. For instance, an image forming apparatus set forth in Patent Document 2 is designed to use microcomputer control for turning on or off power supply to a power supply circuit for power system.
Patent Document 1: Japanese Patent Application Laid-Open Gazette No. 2002-333756
Patent Document 2: Japanese Patent Application Laid-Open Gazette No. 2000-333459